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<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
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<body>
    <script>
        console.log(1 + 1)
        console.log("1" + 1)        // 11
        console.log(1 + "1")        // 11
        console.log(1 - "1")        // 0
        console.log(+"123")         // 隐式转换为数字
    </script>
</body>
</html>